"they must feel they have something solid"
Callam McMillan @ 09:21 said "...As for the logic of pursuing all these big name players, they must feel they have something solid... ".
They don't need anything solid, they just need something that is expensive to defend against. Prior art has no meaning after the patent has been granted. When challenged with a patent suit like this, a company really only has three options:
1) pay someone else to continue to doing what you do
2) pay to change what you do and pay the penalty of having done it 'wrong'
3) pay to try and prove that the USPO was wrong to grant the patent in the first place, and all subsequent judgements that the patent is valid were also wrong.
The extortionists rely on the fact that option one is almost always the cheapest, and remember, if any one of your victims decides that it is cheaper to go with option one, then that is considered evidence that the case is valid and makeing option 3 even more expensive.
If you were curoius why so little that is new or innovative has come out of the US in the last 20 years, now you know.